Information processing system

ABSTRACT

An information processing system according to the present invention includes a plurality of information processing apparatuses connected by a multihop network, and each of the information processing apparatuses includes a first communication unit configured to transmit and receive a first packet including information about a destination address and a second communication unit configured to communicate at a frequency higher than that of the first communication unit and transmit and receive a second packet including a payload, and in each of the information processing apparatuses, when the first communication unit receives the first packet, the second communication unit is woken up, so that efficient data transfer can be achieved while the power consumption is saved.

TECHNICAL FIELD

The present invention relates to an information processing system, andmore particularly, to improvement of data transfer efficiency and powersaving in data transfer in a multihop network.

BACKGROUND ART

There is a technique disclosed in PTL 1 which is a power savingtechnique in data transfer in a multihop network. In the techniquedisclosed in PTL 1, each terminal receives a wake-up signal addressed tothe terminal, and then changes from sleep state to active state toreceive data, and analyzes the destination of data included in thereceived data. When the data are determined to be data addressed toanother terminal as a result of analysis, the terminal transmits awake-up signal to a subsequent terminal.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Laid-Open No. 2010-252165

SUMMARY OF INVENTION Technical Problem

In the technique disclosed in PTL 1, the transfer destination isdetermined by checking the destination address included in the data, andtherefore, each terminal has to wait until a data transfer unit is wokenup. For this reason, in a case of data transfer in a multihop network,it is necessary to wait for waking up a terminal on each hop, and thisreduces the data transfer performance.

Solution to Problem

An information processing system according to the present inventionincludes a plurality of information processing apparatuses connected bya multihop network, and each of the information processing apparatusesincludes a first communication unit configured to transmit and receive afirst packet including information about a destination address and asecond communication unit configured to communicate at a frequencyhigher than that of the first communication unit and transmit andreceive a second packet including a payload, and in each of theinformation processing apparatuses, when the first communication unitreceives the first packet, the second communication unit is woken up, sothat the above problem is solved.

Advantageous Effects of Invention

According the present invention, the power consumed by the secondcommunication unit is reduced, and still, the data transfer performanceis not degraded because of waiting for waking up the secondcommunication unit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a figure illustrating a configuration of processing nodes andconnection between processing nodes according to an embodiment of thepresent invention.

FIG. 2 is a figure illustrating an example of a multihop networkaccording to the present invention.

FIG. 3 is a figure illustrating details of a processing node accordingto the embodiment of the present invention.

FIG. 4 is a figure illustrating details of an example of a datacommunication unit.

FIG. 5 is a figure illustrating an example of a power management packettransfer history table.

FIG. 6 is a figure illustrating details of an example of a powermanagement communication unit.

FIG. 7 is a figure illustrating an example of content of a data packet.

FIG. 8 is a figure illustrating an example of content of a powermanagement packet.

FIG. 9 is a figure illustrating an example of multihop transferaccording to the present invention.

FIG. 10 is a sequence diagram illustrating operation of an example ofmultihop transfer according to the present invention.

FIG. 11 is a figure illustrating an example of a correlation tablebetween a communication port and a processing node of a connectiondestination.

FIG. 12 is a figure illustrating an example of a routing table.

DESCRIPTION OF EMBODIMENTS

[First Embodiment]

FIG. 1 illustrates a processing node 100 and a processing node 101 whichare information processing apparatuses included in an embodiment of aninformation processing system according to the present invention. FIG. 1is a block diagram illustrating an internal configuration of aprocessing node 100 and a processing node 101.

The processing node 100 includes a data processing unit 110 configuredto perform various kinds of arithmetic operations and controls, a datacommunication unit 120 configured to generate a data packet 300including a payload to be transmitted to another processing node andtransmit and receive the data packet 300 to/from another processingnode, a power management unit 130 configured to control the power of thedata communication unit 120, and a power management communication unit140 configured to generate a power management packet 400 paired with thedata packet 300 and transmit and receive the power management packet 400to/from another processing node. In the present embodiment, theprocessing node 101 connected to the processing node 100 and otherprocessing nodes (not shown) are configured to have the samespecification as the processing node 100.

FIG. 7 illustrates a schematic diagram of a configuration content of thedata packet 300 according to the present embodiment. The data packet 300includes, as information, an identifier 301 indicating data transfercontents such as start of a signal and a transfer size, a destinationaddress 302 indicating a processing node of the final transferdestination, and a payload 303 which is actual data. FIG. 8 is aschematic view illustrating configuration contents of the powermanagement packet 400. The power management packet 400 includes, asinformation, an identifier 401 indicating a power management requestcontent including start of a signal and wake-up of the datacommunication unit 120 or start of a signal and stop of the datacommunication unit 120, and a destination address 402 indicating theprocessing node of the final transfer destination.

As shown in FIG. 1, the data communication unit 120 of the processingnode 100 and the data communication unit 120 of the processing node 101are connected via a channel. The power management communication unit 140of the processing node 100 and the power management communication unit140 of the processing node 101 are connected via a channel. Anotherprocessing node connected to the processing node 100 is also connectedin the same manner as the processing node 101. In the presentembodiment, communication between the data communication units 120 ofthe processing nodes is performed with high speed serial communicationin order to exchange data at a high speed. The data communication unit120 can communicate at a frequency in GHz band, for example. Incontrast, the power management packet 400 of which size is smaller thanthe data packet 300 including the payload 303 is exchanged incommunication between the power management communication units 140 ofthe processing nodes, and therefore, the communication need not beperformed at a high speed. Therefore, the communication between the datacommunication units 140 is slower than the communication between thedata communication units 120, and the data communication units 140communicate with each other at, for example, a frequency in MHz band.Therefore, when the data communication unit 120 is woken up, the datacommunication unit 120 consumes higher power than the power managementcommunication unit 140 because of the difference in the frequency of theclock used for transmitting and receiving packets. Because of therelationship of this consumed power, the power consumed by theinformation processing system can be reduced by stopping or hibernatingthe operation of the portion related to the high speed communication ofthe data communication unit 120 by stopping the supply of the clock, forexample. Further, before the transfer of the data packet 300, the datacommunication unit 120 required for transfer of the data packet 300 canbe woken up by using connection between the power managementcommunication units 140.

FIG. 2 illustrates an information processing system 2000 according tothe present embodiment. The information processing system 2000 has amultihop network configuration in which multiple information processingapparatuses are connected with each other. In the drawing, a circledenotes a processing node, and a line denotes a connection betweenprocessing nodes. The information processing system 2000 is athree-dimensional torus network. Each processing node is given anaddress of the processing node which is represented by [x, y, z] (x, y,z=0, 1, 2 . . . ). FIG. 2 illustrates, for example, a position of theprocessing node [1, 0, 0]. The information processing system 2000 is athree-dimensional torus network, but the present invention is notlimited to this configuration. The present invention can also be appliedto various kinds of multihop networks such as a mesh and a ring.

FIG. 3 illustrates a block diagram showing the details of the internalconfiguration of the processing node 100. The data processing unit 110includes a central processing unit (CPU) 111 and a memory 112. The CPU111 performs various kinds of arithmetic operations and controls theprocessing node 100. The memory 112 is used as a storage for storing anintermediate result and a final result of the arithmetic operationprocessing performed by the CPU 111, and is used as a storage forstoring the transmission/reception data.

The data communication unit 120 includes a data transfer control unit121, a data transmission unit 122, and a data reception unit 123. Inaccordance with a command given by the data communication power controlunit 132, the data communication unit 120 has a function of changing allor apart thereof into a power state, and more specifically, the datacommunication unit 120 has a function of hibernating or stopping all ora part thereof, in order to save power. In this case, the low powerstate is a state in which the clock and the power supply are stopped andtherefore data cannot be transmitted or received but the powerconsumption is low. The normal state is a state in which data can betransmitted or received but the consumed power is higher than that inthe low power state. The transition from the low power state to thenormal state is done in the same manner in accordance with the commandgiven by the data communication power control unit 132. In order tochange from the low power state to the normal state or from the normalstate to the low power state, it takes at least several microseconds toseveral dozen microseconds to, e.g., recovery, for example, a clock datarecovery (CDR) circuit although it depends on the degree of low powerconsumption, that is, whether it is hibernation or sleep state. The timerequired for transmission of the state is a time about ten to hundredtimes longer than the transfer delay between processing nodes.

In the present embodiment, when no data communication is performed, thedata communication unit 120 can change all of the data communicationunit 120 into the low power state, and when data communication isperformed, each of the ports of the transmission port 125 and thereception port 127 which are not used for the data communication can bechanged into the low power state. In the present embodiment, the clocksupply and the power supply at each port is stopped, so that each portis stopped, and each port is changed into the low power state. The datacommunication unit 120 has a timer for each port, and when there is nodata communication at the port having received the wake-up request for acertain period of time, e.g., one second, since the reception of thelatest wake-up request given to each of the ports of the transmissionport 125 and the reception port 127, then the data communication unit120 gives a stop request of a corresponding portion to the datacommunication power control unit 132. Therefore, the necessary part ofthe data communication unit 120 can be woken up for a time sufficientfor the transfer of the data packet 300, and even though a command forstop is not actively transmitted from the outside, unnecessary powerconsumption in the data communication unit 120 can be reduced.

Further, when all the ports in the transmission port 125 are in the lowpower state, the data communication unit 120 transmits a stop requestfor stopping the transmission unit 122 to the data communication powercontrol unit 132. Likewise, when all the ports in the reception port 127are in the low power state, the data communication unit 120 transmits astop request for stopping the reception unit 123 to the datacommunication power control unit 132. Further, when all the ports in thetransmission port 125 and the reception port 127 are in the low powerstate, the data communication unit 120 transmits the stop request forstopping the entire data communication unit 120 including the datatransfer control unit 121 to the data communication power control unit132.

The data transfer control unit 121 receives a data transfer command fromthe CPU 111 to generate a data packet 300, and transmits the generateddata packet 300 to the data transmission unit 122. The data transfercontrol unit 121 extracts the destination address 302 included in thedata packet 300 received from another processing node by the datareception unit 123, and determines the address by comparing theextracted destination address 302 and the address of the processing nodein question stored in the memory 134 of the power management unit 130explained later. When the destination address 302 is determined to matchthe address of the processing node in question as a result of thedetermination, the data transfer control unit 121 reads data from thememory 112 or writes the payload 303 to the memory 112 in accordancewith the decoded result of the identifier 301. When the destinationaddress 302 is determined not to match the address of the processingnode in question, the data transfer control unit 121 transmits the datapacket 300 to the data transmission unit 122.

FIG. 4 illustrates a block diagram of the data communication unit 120,which shows the details of the data transmission unit 122 and the datareception unit 123. The data transmission unit 122 includes a transferdestination selection unit 124 and the transmission port 125 which isthe communication port. The transfer destination selection unit 124makes a selection as to which processing node of the processing nodesconnected with the processing node 100 the data packet 300 transmittedfrom the data transfer control unit 121 is to be transferred to, andtransmits the data packet 300 the selected processing node via thetransmission port 125. Each port of the transmission port 125 includes atransceiver for a high speed serial transmission capable ofcommunicating at a frequency in GHz band. Therefore, the power consumedby each port of the transmission port 125 is high because the suppliedclock is high. Each port of the transmission port 125 is connected withthe reception port 127 of another processing node connected.

The transfer destination selection unit 124 selects the transmissiondestination of the data packet 300 by using the power management packettransfer history table 200 as shown in FIG. 5, the routing table 1200 asshown in FIG. 12, and the table 1100 as shown in FIG. 11. As explainedlater, the power management packet transfer history table 200 is storedin the memory 134 of the power management unit 130, and is a tablestoring, as entry information, which port of the transmission port 145of the processing node in question is used when the power managementpacket 400 is transferred to the processing node indicated by thedestination address 402. As shown in the table 1100 explained later,which port of the transmission port 145 of the processing node inquestion is used corresponds to which processing node of anotherprocessing node connected with the processing node in question is usedfor the transfer. The routing table 1200 is stored in the memory 134 ofthe power management unit 130, and is a table indicating a subsequenttransfer destination address when the data packet 300 or powermanagement packet 400 is transferred to the processing node indicated bythe destination addresses 302, 402. The routing table 1200 of FIG. 12 isgenerated on the basis of a policy for selecting the address of thetransfer destination so that the address is caused to be closer to thedestination addresses 302, 402 in the order of x if x does not match, inthe order of y if y does not match, and in the order of z if the z doesnot match, but the routing table 1200 can be regenerated by dynamicallychanging the policy in accordance with the congestion situation of thenetwork due to the transfer of the data packets 300 and the powermanagement packets 400. For example, between the processing nodes wherethe network is congested in the communication in the x direction, thepolicy is changed so that the address is caused to be closer to thedestination addresses 302, 402 in the order of y, z, x or in the orderof z, y, x, and the change is reflected in the routing table 1200. Thetable 1100 is stored to the memory 134 of the power management unit 130,and is a table indicating relationship between the port numbers of thetransmission port 125, the reception port 127, the transmission port145, and the reception port 147, and the connection destinationprocessing node. In the table 1100 of FIG. 11, the port number of eachport is the same.

First, the transfer destination selection unit 124 determines whetherthe destination address 302 of the data packet 300 transmitted from thedata transfer control unit 121 matches the destination address of anentry in the power management packet transfer history table 200. Whenthere is a matching address as a result of the determination, thetransfer destination selection unit 124 transfers the data packet 300via the port corresponding to the port indicated by the entry, which isdetermined to match the data packet 300, of the ports of thetransmission port 125. As explained later, since the communication pathincluding the port corresponding to the destination address of the entryin the power management packet transfer history table 200 has alreadybeen woken up, the data packet 300 is transferred without waiting forthe transition from the low power state to the normal state. Inaddition, the port is woken up as necessary, the power consumed by theinformation processing system 2000 can be reduced.

On the other hand, when there is no matching address, the transferdestination selection unit 124 refers to the routing table 1200 andselects the transfer destination, and obtains information about the portof the transmission port 125 that is required to be woken up in order toperform transfer to the transfer destination selected with reference tothe table 1100, and transmits the wake-up request of the necessary portand the destination address 302 to the data communication power controlunit 132 of the power management unit 130. Upon transmission of thewake-up request and the destination address 302, the transfer selectionunit 124 receives the completion of the wake-up, and executes again thedetermination as to whether the destination address 302 matches thedestination address in the power management packet transfer historytable 200.

The data reception unit 123 includes the arbitration unit 126 and thereception port 127 which is the communication port. Each port of thereception port 127 includes a receiver for high speed serialtransmission capable of communicating at a frequency in GHz band.Therefore, the power consumed at each port of the reception port 127 ishigh because the supplied clock is high. The data reception unit 123receives the data packet 300 transmitted from another processing node atthe reception port 127, and the arbitration unit 126 arbitrates the datapacket 300 transferred from each port of the reception port 127, and thedata reception unit 123 transmits the received data packet 300 to thedata transfer control unit 121. Each port of the reception port 127 isconnected to the transmission port 125 of another processing nodeconnected with the processing node 100.

The power management unit 130 includes a data communication stateobservation unit 131, a data communication power control unit 132, apower management packet history control unit 133, and a memory 134.Hereinafter, each unit will be explained.

The data communication state observation unit 131 obtains informationabout the operation state of the data communication unit 120 bycommunicating with each unit of the data communication unit 120, and canobtain information indicating whether the entire data communication unit120, the entire data transmission unit 122, the entire data receptionunit 123, each port of the transmission port 125, and each port of thereception port 127 are in the low power state or in the normal state.

The data communication power control unit 132 receives a request fromthe CPU 111, the data communication unit 120, the power managementpacket transmission unit 142 explained later, and the power managementpacket reception unit 143, and changes the operation state indicatingwhether the entire data communication unit 120, the entire datatransmission unit 122, the entire data reception unit 123, each port ofthe transmission port 125, and each port of the reception port 127 arein the low power state or in the normal state, and gives an updatecommand of the power management packet transfer history table 200 to thepower management packet history control unit 133. When each port of thetransmission port 125 is changed to the normal state, the datacommunication power control unit 132 changes the necessary portion ofthe data transmission unit 122 and the data transfer control unit 121into the normal state, if the entire data transmission unit 122 and thedata transfer control unit 121 are in the low power state. When eachport of the reception port 127 is changed to the normal state, the datacommunication power control unit 132 changes the necessary portion ofthe data reception unit 123 and the data transfer control unit 121 intothe normal state, if the entire data reception unit 123 and the datatransfer control unit 121 are in the low power state. When the datacommunication power control unit 132 receives a request of transmissionof data from the CPU 111, request for generation of the power managementpacket 400 is sent to a power management packet control unit 141.

The power management packet history control unit 133 updates the powermanagement packet transfer history table 200 on the basis of the commandof the data communication power control unit 132. As explained later,the power management packet transfer history table 200 is a table thathas, as entry information, as to which port of the transmission port 145of the processing node in question is used, that is, which processingnode of other processing nodes connected to the processing node inquestion the transmission is sent to, when the power management packet400 is transmitted to the processing node indicated by the destinationaddress 402. In the power management packet transfer history table 200,registration or deletion is made in an entry on the basis of informationabout the identifier 401 of the power management packet 400, thedestination address 402, and the port number of the transmission port145 used for the transfer. When the identifier 401 is the wake-uprequest, and there is no address matching the destination address 402 inthe power management packet transfer history table 200, the powermanagement packet history control unit 133 registers it as a new entryin the power management packet transfer history table 200, and whenthere is a matching address, the entry having the matching address isoverwritten and updated. When the identifier 401 is the stop request,the entry having the address matching the destination address 402 isdeleted.

The memory 134 stores information about the address of the processingnode in question, the power management packet transfer history table200, the table 1100, and the routing table 1200.

The power management communication unit 140 includes the powermanagement packet control unit 141, the power management packettransmission unit 142, and the power management packet reception unit143. The power management packet control unit 141 generates the powermanagement packet 400 in response to the command given by the datacommunication power control unit 132, and transfers the generated powermanagement packet 400 to the power management packet transmission unit142. The power management packet control unit 141 extracts thedestination address 402 included in the power management packet 400received from the power management packet reception unit 143, andcompares the extracted address 402 and the address of the processingnode in question stored in the memory 134 of the power management unit130, thus determining the address. When the destination address 402matches the address of the processing node in question as a result ofdetermination, the power management packet 400 is not transmitted to thepower management packet transmission unit 142, and when the destinationaddress 402 does not match the address of the processing node inquestion, the power management packet 400 is transmitted to the powermanagement packet transmission unit 142.

FIG. 6 illustrates a block diagram of the power management communicationunit 140 showing the details of the power management packet transmissionunit 142 and the power management packet reception unit 143. The powermanagement packet transmission unit 142 includes the transferdestination selection unit 144 and the transmission port 145. Each portof the transmission port 145 is connected to the reception port 147 ofanother processing node connected to the processing node 100. Theconnection relationship between each port of the transmission port 145and each port of the reception port 147 is stored to the memory 134 asthe table 1100.

The transfer destination selection unit 144 selects to which processingnode of the processing nodes connected to the processing node 100 thepower management packet 400 is, for the power management packet 400transmitted from the power management packet control unit 141, istransferred to by referring to the routing table 1200, and transmits thepower management packet 400 via the transmission port 145 by referringto the table 1100. The transfer destination selection unit 144 decodesthe identifier 401 of the power management packet 400, and when thedecoded result is the wake-up request, the wake-up request for waking-upthe port of the transmission port 125 corresponding to the port of thetransmission port 145 used for the transfer of the power managementpacket 400 as well as information about the destination address 402 andinformation about the number of the port of the transmission port 145used for transfer of the power management packet 400 are transmitted tothe data communication power control unit 132 by referring to the table1100. When the decoded result is the stop request, the transferdestination selection unit 144 refers to the table 1100, and transmitsthe wake-up request for waking up the port of the transmission port 125corresponding to the port of the transmission port 145 used for thetransfer of the power management packet 400 as well as information aboutthe destination address 402 and information about the number of the portof the transmission port 145 used for transfer of the power managementpacket 400 to the data communication power control unit 132. At thisoccasion, the data transmission/reception is treated as a set, and thewake-up request or the stop request for stopping the port of thereception port 127 corresponding to the port of the transmission port125 to which the wake-up request or the stop request is given is alsoperformed at the same time, but in order to achieve more detailed powercontrol, the wake-up or the stop of the data transmission unit 122 andthe data reception unit 123 can be controlled independently.

The power management packet reception unit 143 includes the arbitrationunit 146 and the reception port 147. Each port of the reception port 147is connected to the transmission port 145 of another processing nodeconnected to the processing node 100. The connection relationship ofeach port of the reception port 147 and each port of the transmissionport 145 is stored in the memory 134 as the table 1100. The powermanagement packet reception unit 143 receives the power managementpacket 400 transmitted from another processing node via the receptionport 147, and the arbitration unit 146 arbitrates the power managementpacket 400 transferred from each port, and decodes the identifier 401,and transmits the power management packet 400 to the power managementpacket control unit 141. When the decoded result of the identifier 401is the wake-up request, the power management packet reception unit 143refers to the table 1100, and transmits the wake-up request for wakingup the port of the reception port 127 corresponding to the port ofreception port 147 used for reception to the data communication powercontrol unit 132. When the decoded result of the identifier 401 is thestop request, the power management packet reception unit 143 refers tothe table 1100, and transmits the stop request for stopping the port ofthe reception port 127 corresponding to the port of reception port 147used for reception to the data communication power control unit 132. Atthis occasion, the data transmission/reception is treated as a set, andthe wake-up request or the stop request for waking up/stopping the portof the transmission port 125 corresponding to the port of the receptionport 127 to which the wake-up request or the stop request is given isalso performed at the same time, but in order to achieve more detailedpower control, the wake-up or the stop of the data transmission unit 122and the data reception unit 123 can be controlled independently.

Subsequently, operation of the multihop transfer according to theembodiment will be explained with reference to the sequence diagram asshown in FIG. 10 using an example of transfer shown in FIG. 9 in whichdata are transferred from the processing node 100 via the processingnode 101 and the processing node 102 to the processing node 103. Itshould be noted that the processing node 100 corresponds to the address[3, 6, 5], the processing node 101 corresponds to the address [4, 6, 5],the processing node 102 corresponds to the address [4, 5, 5], theprocessing node 103 corresponds to the address [4, 4, 5], respectively.In the initial state, the entire data communication unit 120 of eachprocessing node is considered to be in the low power state.

First, in step 100, when the processing node 100 transfers data to theprocessing node 103, the CPU 111 of the processing node 100 requests thedata communication power control unit 132 to perform data transmission,of which the final destination is the processing node 103. The CPU 111requests the data communication state observation unit 131 to sendinformation about the state of the data communication unit 120. The datacommunication state observation unit 131 having received the requestchecks the state of the data communication unit 120, and notifies theCPU 111 that the entire data communication unit 120 is in the low powerstate. The CPU 111 having received the notification waits for thewake-up completion notification from the data communication powercontrol unit 132.

Subsequently, in step S101, the data communication power control unit132 commands the power management packet control unit 141 to generatethe power management packet 400 of which identifier 401 is the wake-uprequest with the processing node 103 being the destination on the basisof the request given by the CPU 111. The power management packet 400generated by the power management packet control unit 141 is transmittedto the power management packet transmission unit 142, and as a result ofselection of the relay destination by the transfer destination selectionunit 144, the power management packet 400 is transferred to theprocessing node 101. The transfer destination selection unit 144 decodesthe identifier 401 of the power management packet 400, and the decodedresult is the wake-up request, and therefore, the transfer destinationselection unit 144 refers to the table 1100, and transmits the wake-uprequest for waking up the port of the port number 1 of the transmissionport 125 corresponding to the port used for transfer in the transmissionport 145 to the data communication power control unit 132.

Subsequently, in step S102, on the basis of the wake-up request given bythe transfer destination selection unit 144, the data communicationpower control unit 132 of the processing node 100 starts wake-up of thedata transfer control unit 121, the transfer destination selection unit124, the port of the port number 1 of the transmission port 125, thearbitration unit 126, and the port of the port number 1 of the receptionport 127 corresponding to the wake-up target port of the transmissionport 125. The destination address indicated by the processing node 103and the port number “1” of the port of the transmission port 145connected to the processing node 101 are registered in the entry of thepower management packet transfer history table 200.

Subsequently, in step S103, the processing node 101 receives the powermanagement packet 400 transmitted from the processing node 100, and thepower management packet control unit 141 determines whether thedestination address 402 matches the address of the processing node inquestion. Because the determination result is “not matching”, the powermanagement packet 400 is transmitted to the power management packettransmission unit 142. The transfer destination selection unit 144selects the processing node 102 as the transfer destination, and thepower management packet 400 is transferred to the processing node 102.

Subsequently, in step S104, the result indicating selection of theprocessing node 102 in 5103 is notified to the data communication powercontrol unit 132, so that the processing node 101 starts wake-up of thedata transfer control unit 121, the transfer destination selection unit124, the transmission port 125 corresponding to the transmission port145 used for transmission of the power management packet 400, thearbitration unit 126, and the reception port 127 corresponding to thewake-up target port of the transmission port 125. The destinationaddress indicating the processing node 103 and the port number of theport of the transmission port 145 connected to the processing node 102are registered to the entry of the power management packet transferhistory table 200. In parallel with the matching determination of thedestination address 402 in S103, the arbitration unit 146 decodes theidentifier 401 of the power management packet 400, and confirms that itis the wake-up request. When the notification indicating that theidentifier 401 is the wake-up request is notified to the datacommunication power control unit 132, the reception port 127corresponding to the reception port 147 used for reception of the powermanagement packet 400 and the transmission port 125 corresponding to theport of the wake-up target of the reception port 127 are started to bewoken up.

Subsequently, in step S105, the processing node 102 receives the powermanagement packet 400 transmitted from the processing node 101, and thepower management packet control unit 141 determines whether thedestination address 402 matches the address of the processing node inquestion. Because the determination result indicates that it isaddressed to another processing node, the power management packet 400 istransmitted to the power management packet transmission unit 142. Thetransfer destination selection unit 144 selects the processing node 103as the transfer destination, and the power management packet 400 istransferred to the processing node 103.

Subsequently, in step S106, the result in S105 is notified to the datacommunication power control unit 132, the processing node 102 startswake-up of the data transfer control unit 121, the transfer destinationselection unit 124, the transmission port 125 corresponding to thetransmission port 145 used for transmission of the power managementpacket 400, the arbitration unit 126, and the reception port 127corresponding to the wake-up target port of the transmission port 125.The destination address indicating the processing node 103 and the portnumber of the port of the transmission port 145 connected to theprocessing node 103 are registered to the entry of the power managementpacket transfer history table 200. In parallel with the matchingdetermination of the destination address 402 in 5105, the arbitrationunit 146 decodes the identifier 401 of the power management packet 400,and confirms that it is the wake-up request. When the notificationindicating that the identifier 401 is the wake-up request is notified tothe data communication power control unit 132, the reception port 127corresponding to the reception port 147 used for reception of the powermanagement packet 400 and the transmission port 125 corresponding to theport of the wake-up target of the reception port 127 are started to bewoken up.

Subsequently, in step S107, the processing node 103 receives the powermanagement packet 400 transmitted from the processing node 102, and thepower management packet control unit 141 determines whether thedestination address 402 matches the address of the processing node inquestion. Because the determination result is “matching”, that is, itindicates that the power management packet 400 is addressed to theprocessing node in question, the power management packet 400 is nottransferred to another processing node. The arbitration unit 146 decodesthe identifier 401 of the power management packet 400, and confirms thatit is the wakeup request. When the notification indicating that theidentifier 401 is the wake-up request is sent to the data communicationpower control unit 132, the reception port 127 corresponding to thereception port 147 used for reception of the power management packet 400and the transmission port 125 corresponding to the port of the wake-uptarget of the reception port 127 are started to be woken up.

In steps S108, S109, S110, each processing node sends, to the processingnode of the transmission source of the power management packet 400, anotification indicating that the transmission/reception unit of the datacommunication unit 120 has been woken up and the processing node isready for data communication.

In step S111, the CPU 111 of the processing node 100 receives thewake-up completion notification from the data transfer control unit 121,and requests the data transfer control unit 121 to perform the datatransfer with the processing node 103 being the destination. Whenalready woken up in step S100, the request is given in step S100.

Subsequently, in step S112, the data transfer control unit 121 generatesthe data packet 300, the generated data packet 300 is transmitted to thetransfer destination selection unit 124. As a result of the matchingdetermination between the destination address 302 and the entry in thepower management packet transfer history table 200, the entry registeredin step S102 matches the destination address 302, and therefore, thetransfer destination selection unit 124 selects the processing node 101as the transfer destination, and transmits the data packet 300 to theprocessing node 101.

Subsequently, in step S113, the processing node 101 receives the datapacket 300 transmitted from the processing node 100, and the datatransfer control unit 121 determines whether the destination address 302matches the address of the processing node in question. Because thedetermination result is “not matching”, that is, the data packet 300 isa packet addressed to another processing node, the data packet 300 istransmitted to the data transmission unit 122. As a result of thematching determination between the destination address 302 and the powermanagement packet transfer history table 200, the entry registered instep S104 matches the destination address 302, and therefore, thetransfer destination selection unit 124 selects the processing node 102as the transfer destination, and the data packet 300 is transferred tothe processing node 102.

When the data packet 300 has been received in step S113, the transferreception is notified to the processing node 100 in step S114.

In step S115, the processing node 102 receives the data packet 300transmitted from the processing node 101, the data transfer control unit121 determines whether the destination address 302 matches the addressof the processing node in question. Because the determination result is“not matching”, that is, the data packet 300 is a packet addressed toanother processing node, the data packet 300 is transmitted to the datatransmission unit 122. As a result of the matching determination betweenthe destination address 302 and the power management packet transferhistory table 200, the entry registered in step S106 matches thedestination address 302, and therefore, the transfer destinationselection unit 124 selects the processing node 103 as the transferdestination, and the data packet 300 is transferred to the processingnode 103.

When the data packet 300 has been received in step S115, the transferreception is notified to the processing node 101 in step S116.

Subsequently, in step S117, the processing node 103 receives the datapacket 300 transmitted from the processing node 102, and the datatransfer control unit 121 determines whether the destination address 302matches the address of the processing node in question. Because thedetermination result is “matching”, that is, it indicates that the datapacket 300 is a packet addressed to the processing node in question, theidentifier 301 is decoded, the payload 303 is transferred to the memory112.

When the data packet 300 has been received in step S117, the transferreception is notified to the processing node 102 in step S118.

As described above, in the information processing system 2000 accordingto the present embodiment, each processing node is configured to be ableto control wake-up and stop of the data communication unit 120 inaccordance with transmission/reception of the power management packet400, and therefore, all or a part of the data communication unit 120,except the portion woken up for transmission/reception of the datapacket 300, can be caused to change into the low power state. Therefore,each processing node can save power consumption. In addition, in theinformation processing system 2000 according to the present embodiment,the processing nodes up to the destination processing node performstransmission/reception of the power management packet 400 withoutwaiting for wake-up of the data communication unit 120, and in parallel,the data communication unit 120 of each processing node can be woken up,and further, a portion of the data communication unit 120 of eachprocessing node is woken up in advance on the basis of thetransmission/reception of the power management packet 400, and by usingthe woken up portion, the data packet 300 is transmitted and received,and therefore, this can reduce the waiting time for waiting for the datatransfer due to the transition from the low power state to the normalstate. Therefore, this can reduce the reduction of the data transferperformance caused by the usage of the low power state.

REFERENCE SIGNS LIST

-   100 to 103 processing node-   110 data processing unit-   111 CPU-   112 memory-   120 data communication unit-   121 data transfer control unit-   122 data transmission unit-   123 data reception unit-   124 transfer destination selection unit (of data transmission unit)-   125 transmission port (of data transmission unit)-   126 arbitration unit (of data transmission unit)-   127 reception port (of data transmission unit)-   130 power management unit-   131 data communication state observation unit-   132 data communication power control unit-   133 power management packet history control unit-   134 memory-   140 power management communication unit-   141 power management packet control unit-   142 power management packet transmission unit-   143 power management packet reception unit-   144 transfer destination selection unit (of power management packet    transmission unit)-   145 transmission port (of power management packet transmission unit)-   146 arbitration unit (of power management packet transmission unit)-   147 reception port (of power management packet transmission unit)-   200 power management packet transfer history table-   300 data packet-   301 identifier (of data packet)-   302 destination address (of data packet)-   303 payload (of data packet)-   400 power management packet-   401 identifier (of power management packet)-   402 destination address (of power management packet)-   1200 routing table-   2000 information processing system    FIG. 1-   100 PROCESSING NODE-   110 DATA PROCESSING UNIT-   120 DATA COMMUNICATION UNIT-   130 POWER MANAGEMENT UNIT-   140 POWER MANAGEMENT COMMUNICATION UNIT CONNECTION WITH ANOTHER    PROCESSING NODE)-   101 PROCESSING NODE    FIG. 3-   100 PROCESSING NODE-   110 DATA PROCESSING UNIT-   112 MEMORY-   130 POWER MANAGEMENT UNIT-   131 OBSERVATION UNIT-   132 POWER CONTROL UNIT-   133 HISTORY CONTROL UNIT-   134 MEMORY-   120 DATA COMMUNICATION UNIT-   121 DATA TRANSFER CONTROL UNIT-   122 TRANSMISSION UNIT-   123 RECEPTION UNIT-   140 POWER MANAGEMENT COMMUNICATION UNIT-   141 POWER MANAGEMENT PACKET CONTROL UNIT-   142 TRANSMISSION UNIT-   143 RECEPTION UNIT CONNECTION WITH ANOTHER PROCESSING NODE)    FIG. 4-   120 DATA COMMUNICATION UNIT-   121 DATA TRANSFER CONTROL UNIT-   122 TRANSMISSION UNIT-   123 RECEPTION UNIT-   124 TRANSFER DESTINATION SELECTION UNIT-   126 ARBITRATION UNIT    FIG. 5-   200 DESTINATION ADDRESS PORT NUMBER OF TRANSMISSION PORT 145 USED    FOR TRANSFER)    FIG. 6-   140 POWER MANAGEMENT COMMUNICATION UNIT-   141 POWER MANAGEMENT PACKET CONTROL UNIT-   142 TRANSMISSION UNIT-   143 RECEPTION UNIT-   144 TRANSFER DESTINATION SELECTION UNIT-   146 ARBITRATION UNIT    FIG. 7-   301 IDENTIFIER-   302 DESTINATION ADDRESS-   303 PAYLOAD    FIG. 8-   401 IDENTIFIER-   402 DESTINATION ADDRESS    FIG. 9

TRANSFER PATH

FIG. 10

-   100 PROCESSING NODE-   101 PROCESSING NODE-   102 PROCESSING NODE-   103 PROCESSING NODE

LOW POWER STATE)

FIG. 11

PORT NUMBER OF TRANSMISSION PORT 145

PORT NUMBER OF RECEPTION PORT 127

CONNECTION DESTINATION PROCESSING NODE

FIG. 12

NEXT TRANSFER DESTINATION

FINAL DESTINATION

The invention claimed is:
 1. An information processing system includinga plurality of information processing apparatuses connected by amultihop network, each of the information processing apparatusescomprising: a first communication unit configured to transmit andreceive a first packet including information about a destinationaddress: and a second communication unit configured to communicate at afrequency higher than that of the first communication unit, and transmitand receive a second packet including a payload to the destinationaddress, wherein in each of the information processing apparatuses, whenthe first communication unit receives the first packet and the firstpacket is addressed to the information processing apparatus, the secondcommunication unit is woken up.
 2. The information processing systemaccording to claim 1, wherein each of the information processingapparatuses includes a memory, the memory stores information about atransfer destination of the first packet, and the second packet istransferred on the basis of information about the transfer destination.3. The information processing system according to claim 2, wherein thememory of each information processing apparatus further stores a routingtable and information about an address of each of the informationprocessing apparatuses, and each of the information processingapparatuses determines whether the destination address matches theaddress of each of the information processing apparatuses, and when adetermination result indicates non-matching, the first packet istransferred on the basis of the routing table.
 4. The informationprocessing system according to claim 2, wherein the second communicationunit has a communication port for each information processing apparatusof connection destination among the plurality of information processingapparatuses, and wakes up, hibernates, or stops each communication portin accordance with the information about the transfer destination. 5.The information processing system according to claim 4, eachcommunication port of the second communication unit is hibernated orstopped after a predetermined period of time passes since wake-up wherethe first communication unit receives the first packet.
 6. Theinformation processing system according to claim 1 comprising: a firstchannel configured to transmit the first packet; and a second channelconfigured to transmit the second packet.
 7. The information processingsystem according to claim 1, wherein the multihop network is athree-dimensional torus network.
 8. The information processing systemaccording to claim 1, wherein the second communication unit communicatesusing high speed serial transmission.
 9. The information processingsystem according to claim 1, wherein the first communication unitcommunicates in MHz band, and the second communication unit communicatesin GHz band.